Corrective device for secondary clocks



April 21, 1936. A. 1.. DENNISTON 2,037,88?

CORRECTIVE DEVICE FOR SECONDARY CLOCKS Original Filed Aug. 29, 1925 & \q INVENroR Patented Apr. 21, 1936 CORRECTIVE DEVICE FOR SECONDARY CLOCKS Adolph L. Denniston, Chicago, Ill., assignor, by

mesne assignments, to Stromberg Electric Company, a. corporation of Delaware Application August 29, 1925, Serial No. 53,231 Renewed August 23, 1934 14 Claims.

My invention relates to corrective devices to correct the time of any secondary apparatus controlled by a master clock in the event that the time of any secondary apparatus is out of synchronism with the master clock due to temporary interruptions in the current supply or for other reasons.

One of the objects of my invention is to provide a corrective device which can beused in connection with the usual two-wire relay circuit.

A further object of my invention is to provide a corrective device which can be readily combined with existing types of mechanisms.

A further object is to provide a corrective de- 15 vice having provisions for correcting a plurality of secondary devices individually without the use of electrical contacts in the secondary devices.

Further objects will appear from the description and claims.

90 In the drawing, the figure shows diagrammatically parts of the secondary and master clock with the relay, corrective device, and wiring arrangements. 7

Referring to the drawing in detail, the parts of :5 the secondary clock shown comprises a secondary impulse electromagnet I in the relay circuit, an armature 2 controlled by this electromagnet, a lever 3 on which this armature is mounted, a pawl lpivoted to the upper end of this lever 3, and a 20 ratchet 5" actuated by this pawl.

The relay shown comprises an electromagnet 6 in the master clock contact circuit, and a switch 1 controlled by this electromagnet and controlling the relay circuit through the secondary impulse 85 magnet. The master clock mechanism shown comprises merely a time-controlled periodic con- ,tact device 8 which is ordinarily controlled by the master clock in such a; way as to close the circuit through the relay magnet once per minute. 40 The corrective device showncomprises a high frequency switch 9 for advancing such secondary clocks as may have gotten behind the master clock, a cam member l mounted on a shaft ll driven by the master clock for periodically plac- 45 mg the high frequency switch 9 in parallel with the low frequency switch 8 to control the relay magnet circuit, a pivoted arm l2 for periodically rendering ineifective the secondary clock pawls 4 of such secondary clocks as may have gotten ahead of the master clock, a polarized relay l3 in the relay circuit for controlling this lever [2, a pole-changing or current-reversing device M for periodically reversing the relay circuit connections and a cam I mounted on the master 55 clock-driven cam shaft I l for periodically energizing the electro-magnet l6 of the pole-changing device for causing reversal of the relay circuit magnets.

When the electro-magnet I6 is not energized the armatures l6a are not attracted 5 and remain in the position shown in the drawing, in which the line l6b is connected with the battery through the contact I60 and the lead l8 and the line "id is connected with the battery through the contact l6e and the lead I6 10 When, however, the electro-magnet I6 is energized the armatures Ilia are attracted and engage the contacts I69 and lGh respectively so that the line IE1) is then connected with the battery through the contact I60 and lead I61, and the line lid is connected with the battery through the contact i671. and lead l8.

The cam l 5 which controls the reversal of current in the relay circuit may be timed so that the circuit from the battery I! through the conductors l8 and l9,.contacts 20 and 2|, conductor 22, magnet l6, and conductor 23 is closed from 55 minutes and 10 seconds after the hour to 59 minutes and 50 seconds after the hour. The cam III which controls the placing of the high frequency switch 9 in parallel with the low frequency switch 8 may be timed so that the contacts 24 and 25 will be in engagement with each other from 59 minutes and 15 seconds past the hour to 59 minutes and 45 seconds after the hour. The high frequency switch is so controlled by the master clock thatthe contacts make and break the circuit every two seconds so that during the thirty seconds in which the high frequency switch is in parallel with the low frequency switch it will cause 15 impulses to pass through the relay magnet 6,pthe circuit being through the conductors l8, l9 and 26, contacts 24, and 25, high frequency switch 9, conductor 21, magnet 6 and conductors 28 and 23, back to the battery.

When the current which flows through the coil of the'polarized relay I3 is in one direction, the

action'of the electro-magnet is such as to tend to raise the lever l2 which is pivoted at 29. When a current through the polarized relay is in the opposite direction, the action is such as to tend to lower the lever. This polarized relay, as is the case with all polarized relays of the type shown, comprises a permanently magnetized member, in this case movable with the lever I2,

the tendency of which is to move in one direction when the current flow through the coil of the relay is in one direction and the tendency of which is to move in the opposite direction when the flow through the relaycoil is reversed. The

shaft 3ll on which the ratchet wheel on the secondary clock is mounted, has mounted thereon a disk 3| having a notch 32 therein for cooperation with a pin 33 on the lever |2. This notch is so positioned that if the secondary clock is in synchronism with the master clock, the notch will come opposite the pin on the lever at 59 minutes after the hour. During the period from 55 minutes and 10 seconds past the hour to 59 minutes and .50 seconds after the hour (by master clock time) when the contacts 20 and 2| are held in engagement with each other by the cam IS, the impulses through the polarized magnet i3 are such as to tend to raise the lever i2 and bring the pin- 33 into engagement with the disk 3|. If, however, the secondary clock is not fast, the pin 33 will simply engage the circular edge of the disk 3| and will not prevent movement of the ratchet 5 under the action of the pawl 4. If, however, any one of the secondary clocks is a few minutes fast, the notch 32 in the disk will be brought opposite the pin 33 on the lever some time before the end of the hour, (by master clock time) and the energization of the polarized magnet l3 will raise the lever and bring the pin 33 into the notch 32, allowing the lever to rise higher than when the pin on the lever simply engaged the circular edge of the disk. This excess movement ofthe lever brings the pin 34 on the end of the lever behind the downwardly extending projection 35 on the pawl 4, and renders this pawl ineifective to engage the teeth of the ratchet 5 in the oscillatory movement of the lever 3 on which the armature 2 is mounted. This armature lever is pivoted at 36 and a tension spring 31 is provided tending to hold the armature 2 away from the electro-magnet. When the lever l2 controlled by the polarized magnet is in its upper-.

most'position with the pin 33 entering the notch 32 on the disk, and secondary impulse magnet is energized to draw the armature toward it, the lower end of the extension 35 on the pawl 4 strikes against the pin 34 on the lever 3 and throws the point 38 of the pawl away from the teeth 39 of the ratchet wheel, so that oscillation of the pawl-carrying lever 3 has no effect on the ratchet wheel. Any secondary clocks which have gotten ahead of the master clock will thus be held at one minute of the hour so long as the contacts 20 and 2| are in engagement with each other. However, just 10 seconds before the end of the hour (by master clock time) the contacts 20 and 2| are separated so that the next impulse through the coil of the polarized relay |3 will be in a direction to lower the lever l2 and permit the pawl 4 to become effective again. Any secondary clocks which may have gotten ahead of the master clock are thus held at one minute of the hour (by master clock time) until 10 seconds before the end of the hour, so that the next impulse through the secondary impulse magnet will bring them to the even hour in synchronism with the master clock.

In the event that any of the secondary clocks may have gotten a few minutes slow, as compared with the master clock, they are automatically stepped upjust before the end of the hour by means of the high frequency contact device 9. This high frequency contact device is placed in parallel with the minute contact device at 45' seconds before the end of the hour and remains thus until 15 seconds before the end of the hour.

During these 30 seconds it causes 15 impulsesof the secondary impulse magnet I. This causes 15 rapid oscillations of the pawl-carrying levers master clock and the remaining 12 rapid oscillations of the pawl-carrying lever will be wasted so far as any movementof the ratchet wheel is concerned, as the pin 33 on the lever controlled by the polarized magnet will drop into the notch 32 on the disk when the secondary clock shows one minute of the hour, and the pin 34 on the lever will render the ratchet actuating pawl 4 ineffective to actuate the ratchet during the remaining l2 oscillations of the pawl-carrying lever.

In the claims where I have used the expression secondary clock it will be understood as including broadly secondary clock mechanism, such as time controlled workmens time recorders, etc.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A secondary clock comprising an impulse magnet for controlling the secondary clock movement, a relay and relay circuit in which said secondary impulse magnet is connected, a master clock comprising a time-controlled contact device for normally controlling the relay to control the secondary magnet, and a corrective device comprising a high frequency time controlled contact device for occasionally controlling the relay to advance any secondary apparatus which may be slow as compared with the master clock, master clock controlled means for periodically rendering the high frequency switch effective to control the relay, a polarized magnet in the relay circuit, master clock controlled means for periodically reversing the relay circuit connections and thus reversing the connections for the polarized magnet independently of the time of the secondary clock, and means controlled by the time of the secondary clock and also by energization of said polarized magnet during the sending of the high frequency impulses for rendering the secondary impulse magnet ineffective to advance the secondary clock mechanism in the event that the secondary clock is fast, said last means comprising a member controlled by the polarized magnet and by the secondary clock, which tends to move in one direction for one direction of current flow in the relay circuit and in another direction upon a reversal of this current flow, and means for preventing movement of said member in one direction unless the secondary clock is fast.

2. A secondary clock comprising an impulse magnet for controlling the secondary clock movement, a relay and relay circuit in which said secondary impulse magnet is connected, a master clock comprising a time-controlled contact device for normally controlling the relay to control the secondary magnet, and a corrective device comprising a high frequency time controlled contact device for occasionally controlling the relay to advance any secondary apparatus which may be slow as compared with the master clock, master clock controlled means for periodically rendering the high frequency switch effective to control the relay, a polarized magnet in the relay circuit, master clock controlled means for periodically reversing the relay circuit connections and secondary clock mechanism in the event that the.

secondary clock is fast, said last means comprising a member controlled by the polarized magnet and by the secondary clock, which tends to move in one direction for. one direction of current flow in the relay circuit and in another direction upon a reversal of this current now, and means for preventing movement of said member in one direction unless the secondary clock is fast, said secondary clock comprising a ratchet and a pawl for driving said ratchet driven by said impulsemagnet, said member engaging said pawl to render it inefiective to operate said ratchet it the secondary clock is iast.

3. A secondary clock for use in synchronized clock systems and comprising a non-polarized im- .pulse magnet which by its own action efiects ell advancing movements of the clock which are required for normal step-by-step advance or for accelerating the clock if the same is slow, and a ratchet actuated by said impulse magnet, with means at each secondary clock, including a polar ized magnet controlled by master clock apparatus for suspending the advance of said secondary clock and rendering said impulse magnet ineii ec= tive to cause force to be exerted on said ratchet under certain chronological conditions of the clock and permitting a reinitiated advance of the clock under the action of the impulse magnet after its action has been suspended, and means including a single line circuit extending into the clock from the master clock for sending thereinto from the master clock both the normal and "fast impulses which normally advance andaccelerate the clock and for also transn'iitting thereto current of special characteristics which upon its recepticn by the clock is adapted to reinitiate an advance thereof after its operation has been suspended.

4. In a secondary apparatus for use in a timecontrolled system, an impulse magnet, an actuating member controlled thereby, a ratchet wheel operated by said member to periodically advance said apparatus under control of said impulse magnet, a second magnet in circuit with said impulse magnet and concurrently energized therewith, and means controlled by said second magnet and operated only when said apparatus is in a particular predetermined chronological position for mechanically preventing eifective engagement of said actuating member with said ratchet wheel, thereby preventing advance of said apparatus.

5. In a secondary apparatus for use in a timecontrolled system, an impulse magnet, an actuating member controlled thereby, a ratchet wheel operated by said member to periodically advance said apparatus under control of said impulse magnet, a second magnet in circuit with said impulse magnet and concurrently energized therewith, and means controlled by said second magnet and operative only when said apparatus is in a particular predetermined chronological position for mechanically preventing effective engagement of said actuating member with said ratchet wheel and for holding said ratchet wheel against move ment, thereby preventing advance of said apparatus.

6. In a secondary apparatus for use in a timecontrolled system, an impulse magnet, a ratchet and pawl controlled by said impulse magnet to effect all advancing movement of said apparatus, means for holding said ratchet to prevent movement of said apparatus, and means for preventing said pawl irom exerting driving force on said ratchet by the energlzation oi'said impulse magnet while said holding means are eflcctive.

' 7. In a secondary apparatus for'use in a timecontrolled system,-an impulse-magnet, a ratchet and pawl controlled by said-impulse magnet to eil'ect all advancing movement of said apparatus, a 'secondmagnet, and means controlled by said second magnet and operative only when said apparatus is in a'particular chronological position for preventing movement of said ratchet and for mechanically preventing said pawl from exerting driving force on said ratchet when said-impulse magnet is; energized. I

8. In a secondary apparatus for use in a timecontrclled system, an impulse magnet having an armature and pawl, a ratchet wheel normally engaged by said pawl, and means operative only when said apparatus is in a particular chronological pcsition for mechanically disengaging said pawl from ratchet wheel when said armature is-clisplaced by the energization of said magnet and thereby preventing actuation of said ratchet wheel.

A secondary c'ocl: for use in a synchronized clocis system of the impulse type wherein each secondary impulse clock is advanced by regularly recurring impulses and accelerated it slow by more recurring current impulses comprising an electromagnetic actuating device, a ratchet actuated oy said electromagnetic device, means controlled. by the chronological condition of the secondary o cclz for rendering said electromagnetic device ineffective to cause a driving force to he exerted on said ratchet andcontrolled by a reversal of current for rendering said electromagnetic device effective to cause force to be exerted on said ratchet.

til. A, secondary clock for use in a synchronized clock system of the impulse type wherein each secondary impulse clock is advanced by regularly recurring impulses in one certain direction and accelerated it slow by more rapidly recurring current impulses comprising an electromagnetic aclogical condition of the secondary clock for rendering said electromagnetic device ineffective to cause a driving force to be exerted on said ratchet and controlled by a reversal of current for rendering said electromagnetic device effective under impulses in said one certain direction to cause force to be exerted on said ratchet.

11. In a. secondary apparatus for use in a time controlled system, an impulse magnet having an armature and pawl, a ratchet wheel normally engaged by said pawl, and means dependent upon the chronological condition of said apparatus for preventing eifective engagement of said pawl with said ratchet wheel when said magnet is energized, thereby preventing advance of said ratchet wheel.

12. In a secondary apparatus for use in a time controlled system, an impulse magnet having an operating pawl, a ratchet wheel engaged by said pawl to advance said apparatus under control of 1 impulses received by said magnet, and means dependent upon the chronological position 01' said secondary apparatus for preventing said pawl from exerting driving force on said ratchet under continued reception of impulses by said magnet.

13. In a time controlled system in which a master apparatus transmits operating and synchronizing impulses over a common circuit to secondary apparatus, an impulse magnet in said secondary apparatus connected to said line circuit to receive all of said impulses, an operating pawl and a ratchet wheel controlled by said magnet to advance said secondary apparatus, and means operative only when said secondary apparatus is in a predetermined chronological position for preventing said pawl from exerting driving force on said ratchet.

14. In a secondary apparatus for use in a timecontrolled system, an impulse magnet, an actuating member controlled thereby to eiifect all advancing movements of said apparatus. a second magnet associated with said impuise'magnet and concurrently energized therewith, means controlled by said second magnet for blocking said actuating member so that the energization of said impulse magnet is inefl'ective, and means for preventing the operation oi said last means upon each energization oi said magnet until said apparatus reaches a particular predetermined chronological position.

A. L. DENNISTON. 

